106 research outputs found
Effect of Changing the Vocal Tract Shape on the Sound Production of the Recorder: An Experimental and Theoretical Study
Changing the vocal tract shape is one of the techniques which can be used by
the players of wind instruments to modify the quality of the sound. It has been
intensely studied in the case of reed instruments but has received only little
attention in the case of air-jet instruments. This paper presents a first study
focused on changes in the vocal tract shape in recorder playing techniques.
Measurements carried out with recorder players allow to identify techniques
involving changes of the mouth shape as well as consequences on the sound. A
second experiment performed in laboratory mimics the coupling with the vocal
tract on an artificial mouth. The phase of the transfer function between the
instrument and the mouth of the player is identified to be the relevant
parameter of the coupling. It is shown to have consequences on the spectral
content in terms of energy distribution among the even and odd harmonics, as
well as on the stability of the first two oscillating regimes. The results
gathered from the two experiments allow to develop a simplified model of sound
production including the effect of changing the vocal tract shape. It is based
on the modification of the jet instabilities due to the pulsating emerging jet.
Two kinds of instabilities, symmetric and anti-symmetric, with respect to the
stream axis, are controlled by the coupling with the vocal tract and the
acoustic oscillation within the pipe, respectively. The symmetry properties of
the flow are mapped on the temporal formulation of the source term, predicting
a change in the even / odd harmonics energy distribution. The predictions are
in qualitative agreement with the experimental observations
Microwave neural processing and broadcasting with spintronic nano-oscillators
Can we build small neuromorphic chips capable of training deep networks with
billions of parameters? This challenge requires hardware neurons and synapses
with nanometric dimensions, which can be individually tuned, and densely
connected. While nanosynaptic devices have been pursued actively in recent
years, much less has been done on nanoscale artificial neurons. In this paper,
we show that spintronic nano-oscillators are promising to implement analog
hardware neurons that can be densely interconnected through electromagnetic
signals. We show how spintronic oscillators maps the requirements of artificial
neurons. We then show experimentally how an ensemble of four coupled
oscillators can learn to classify all twelve American vowels, realizing the
most complicated tasks performed by nanoscale neurons
Rare De Novo Missense Variants in RNA Helicase DDX6 Cause Intellectual Disability and Dysmorphic Features and Lead to P-Body Defects and RNA Dysregulation
Item does not contain fulltex
The DDX6-4E-T interaction mediates translational repression and P-body assembly
This is the final version of the article. Available from the publisher via the DOI in this record.4E-Transporter binds eIF4E via its consensus sequence YXXXXLΦ, shared with eIF4G, and is a nucleocytoplasmic shuttling protein found enriched in P-(rocessing) bodies. 4E-T inhibits general protein synthesis by reducing available eIF4E levels. Recently, we showed that 4E-T bound to mRNA however represses its translation in an eIF4E-independent manner, and contributes to silencing of mRNAs targeted by miRNAs. Here, we address further the mechanism of translational repression by 4E-T by first identifying and delineating the interacting sites of its major partners by mass spectrometry and western blotting, including DDX6, UNR, unrip, PAT1B, LSM14A and CNOT4. Furthermore, we document novel binding between 4E-T partners including UNR-CNOT4 and unrip-LSM14A, altogether suggesting 4E-T nucleates a complex network of RNA-binding protein interactions. In functional assays, we demonstrate that joint deletion of two short conserved motifs that bind UNR and DDX6 relieves repression of 4E-T-bound mRNA, in part reliant on the 4E-T-DDX6-CNOT1 axis. We also show that the DDX6-4E-T interaction mediates miRNA-dependent translational repression and de novo P-body assembly, implying that translational repression and formation of new P-bodies are coupled processes. Altogether these findings considerably extend our understanding of the role of 4E-T in gene regulation, important in development and neurogenesis.BBSRC [BB/J00779X/1 to N.S.]; CNRS PICS (to D.W.); Agence Nationale pour la Recherche [ANR-14-CE09-0013-01ANR to D.W.]; Gates Cambridge Foundation (to A.K.); Fondation Wiener – Anspach of the Université Libre de Bruxelles and the Cambridge Newton Trust (C.V.). Funding for open access charge: BBSRC
High Abundance Proteins Depletion vs Low Abundance Proteins Enrichment: Comparison of Methods to Reduce the Plasma Proteome Complexity
BACKGROUND:
To date, the complexity of the plasma proteome exceeds the analytical capacity of conventional approaches to isolate lower abundance proteins that may prove to be informative biomarkers. Only complex multistep separation strategies have been able to detect a substantial number of low abundance proteins (<100 ng/ml). The first step of these protocols is generally the depletion of high abundance proteins by the use of immunoaffinity columns or, alternatively, the enrichment of by the use of solid phase hexapeptides ligand libraries.
METHODOLOGY/PRINCIPAL FINDINGS:
Here we present a direct comparison of these two approaches. Following either approach, the plasma sample was further fractionated by SCX chromatography and analyzed by RP-LC-MS/MS with a Q-TOF mass spectrometer. The depletion of the 20 most abundant plasma proteins allowed the identification of about 25% more proteins than those detectable following low abundance proteins enrichment. The two datasets are partially overlapping and the identified proteins belong to the same order of magnitude in terms of plasma concentration.
CONCLUSIONS/SIGNIFICANCE:
Our results show that the two approaches give complementary results. However, the enrichment of low abundance proteins has the great advantage of obtaining much larger amount of material that can be used for further fractionations and analyses and emerges also as a cheaper and technically simpler approach. Collectively, these data indicate that the enrichment approach seems more suitable as the first stage of a complex multi-step fractionation protocol
SUMO regulates p21Cip1 intracellular distribution and with p21Cip1 facilitates multiprotein complex formation in the nucleolus upon DNA damage
We previously showed that p21Cip1 transits through the nucleolus on its way from the nucleus to the cytoplasm and that DNA damage inhibits this transit and induces the formation of p21Cip1-containing intranucleolar bodies (INoBs). Here, we demonstrate that these INoBs also contain SUMO-1 and UBC9, the E2 SUMO-conjugating enzyme. Furthermore, whereas wild type SUMO-1 localized in INoBs, a SUMO-1 mutant, which is unable to conjugate with proteins, does not, suggesting the presence of SUMOylated proteins at INoBs. Moreover, depletion of the SUMO-conjugating enzyme UBC9 or the sumo hydrolase SENP2 changed p21Cip1 intracellular distribution. In addition to SUMO-1 and p21Cip1, cell cycle regulators and DNA damage checkpoint proteins, including Cdk2, Cyclin E, PCNA, p53 and Mdm2, and PML were also detected in INoBs. Importantly, depletion of UBC9 or p21Cip1 impacted INoB biogenesis and the nucleolar accumulation of the cell cycle regulators and DNA damage checkpoint proteins following DNA damage. The impact of p21Cip1 and SUMO-1 on the accumulation of proteins in INoBs extends also to CRM1, a nuclear exportin that is also important for protein translocation from the cytoplasm to the nucleolus. Thus, SUMO and p21Cip1 regulate the transit of proteins through the nucleolus, and that disruption of nucleolar export by DNA damage induces SUMO and p21Cip1 to act as hub proteins to form a multiprotein complex in the nucleolus
Patterns of organisation in changing landscapes: implications for the management of biodiversity
Despite the widespread need to predict and assess the effects of landscape change on biodiversity, the array of tools available for this purpose is still limited. Species’ patterns and human activities such as land use respond to the environment on their own suite of scales in space and time so that their interactions are overlapping but complex. It is difficult, therefore, to relate biodiversity to patterns described solely by metric assessments of spatial heterogeneity. In this methodological paper, we therefore propose consideration of two measures of landscape organisation which focus on the relationships between different properties of the landscape system (e.g., soil type distribution, land use distribution), rather than on their description alone. Alpha organisation measures the degree to which the distribution of features such as land use deviate from a random distribution, measured here as fractal dimension from the semivariogram of a variable describing agricultural intensity. Beta organisation measures the degree of deviation by which the spatial distribution of one property (e.g., human land use) is independent of the distribution of another (e.g., soil type) and was derived from relative mutual information (= redundancy) between the ‘agricultural land use’ and ‘soil types’. These measures are illustrated in a rural landscape of the lower Seine valley, at two scales of observation, and at two dates (1963 and 1999) separated by substantial agricultural change due the European Common Agricultural Policy (= CAP). The results show that analysis of patterns of agricultural activity across a range of spatial scales (α organisation), or across the pattern of spatial variation in soil types (β organisation) reveal how the agricultural actors respond to environmental constraints at different scales. This organisation concept relates to the metastability of landscape systems, and suggest possible correlation between high values of landscape organisation and high levels in biodiversity
- …